How Close Is Iran to a Nuke, Really?

Iran now has enough low-enriched uranium to make one atomic bomb—at least theoretically. Independent analysts say that became clear after the U.N.'s International Atomic Energy Agency issued its latest inspection report on Feb. 19, revealing the presence of 1,010 kilograms of the material Washington and the Europeans hoped would never exist.

It's a grim milestone on the road to nuclear perdition; but, then, Iran has passed so many of those in the last five years. And many, like this one, were not quite as dramatic as initial reports implied. U.N. inspectors quickly downplayed stories that they'd not only underestimated the quantities in earlier reports, but they might even have been deceived. Sources close to the IAEA also suggested that it would take about 50 percent more of the low-enriched stuff to process enough high-enriched stuff to make a bomb (a target that could be reached later this year). And in any case, the threat is hypothetical: the potential fuel for one device does not a nuclear power make. The question of whether Tehran moves to arm itself with nukes today, tomorrow, next year, next decade or ever remains open. Indeed, the Iranians say they have no such intentions; they're processing the uranium for future power plants like the one at Bushehr that was fired up in a trial run last week.

Is there any red line Iran may hesitate to cross? The last big one—so big it could start a war—is what's known as "breakout": effectively renouncing the Nuclear Non-Proliferation Treaty to which Iran is a signatory, halting U.N. inspections and opening the way for a full-bore nuclear-weapons program. What Iran has now achieved, says former inspector David Albright, of the Institute for Science and International Security, is "breakout capability." Perhaps that's all Iran really wants: enough mastery of enrichment to keep the world guessing about its nuclear defenses without provoking massive retaliation. IAEA Director-general Mohamed ElBaradei tends toward this view. But as Albright says, "We just don't know … I think people should be worried."

Already, Iran has curtailed its cooperation with the IAEA, making it much harder for inspectors to uncover any secret facilities. And it has yet to give a convincing explanation about evidence that it was running a secret program in the past specifically designed to create nukes. A 2007 American National Intelligence Estimate concluded Iran had stopped that program in 2003, but there is no guarantee it hasn't cranked it up again.

So what should Europe and the U.S. do? Obama's team has yet to articulate policy in detail, but the likely emphasis will be on talk—even as it tries to tighten sanctions on Tehran. Iran's economy has become much more vulnerable as oil prices plunge. Albright thinks gasoline supplies should be cut off to a country that, while it produces a great deal of crude, has almost no refining capacity. A process of dialogue may be long and frustrating, but the bottom line is now measurable: 1,010 kilograms of failure.